More order with less judgment: An optimal theory of the evolution of cooperation

Moral systems are key to distinguishing between "good" and "bad" and are essential to the establishment of social orders. For instance, a rule of thumb for maintaining cooperation within a sizable group is to help those who have a good reputation and avoid those who seem bad. However, the moral standard for what is good and what is bad is not necessarily unique and often diverges across societies.

"What moral standards best promote cooperation among those who are willing to freeload on others' efforts?" Sasaki asks. "There is no definitive consensus on the question, and it remains unclear even how those who refuse to help the bad should be assessed."